Conor McGregor accepted the challenge after he was called out by Rafael dos Anjos at UFC Vegas 14.
Dos Anjos trained his sights on fighting Irish superstar McGregor following his victory over Paul Felder on Saturday.
Felder gave a good account of himself after stepping in as a late replacement for Islam Makhachev, who pulled out of the lightweight contest with a staph infection.
Dos Anjos wasted no time in turning his attention to McGregor after earning a split decision victory, with Khabib Nurmagomedov having announced his retirement last month.
“I think me and Conor is the fight to make,” said the Brazilian.
“If Khabib has really retired it will leave the division wide open and I think me and Conor are the only real champions in the division.”
Former two-weight champion McGregor is set to fight American Dustin Poirier next, but declared he will be ready to step into the Octagon with Dos Anjos after that contest.
He tweeted: “Dustin first, but I’m down for it all.”